Three-dimensional visualization of rat retina by X-ray differential phase contrast tomographic microscopy

The retina is one of the most tiny and sophisticated tissues of the body. Three dimensional (3D) visualization of the whole retina is valuable both in clinical and research arenas. The tissue has been predominantly assessed by time-consuming histopathology and optical coherence tomography (OCT) in research and clinical arenas. However, none of the two methods can provide 3D imaging of the retina. The purpose of this study is to give a volumetric visualization of rat retina at submicron resolution, using an emerging imaging technique-phase-contrast X-ray CT. A Sprague-Dawley (SD) rat eye specimen was scanned with X-ray differential phase contrast tomographic microscopy (DPC-microCT) equipped at the Swiss Light Source synchrotron. After scanning, the specimen was subjected to routine histology procedures and severed as a reference. The morphological characteristics and signal features of the retina in the DPC-microCT images were evaluated. The total retina and its sublayers thicknesses were measured on the DPC-microCT images and compared with those obtained from the histological sections. The retina structures revealed by DPC-microCT were highly consistent with the histological section. In this study, we achieved nondestructive 3D visualization of SD rat retina. In addition to detailed anatomical structures, the objective parameters provided by DPC-microCT make it a useful tool for retinal research and disease diagnosis in the early stage.